In many electronic systems the subassemblies that make up the system use large amounts of current at low voltages. For example, in large computer systems subassemblies often draw hundreds of amperes of current at only 5 volts. This combination of high current and low voltage requires, among other things, that the electrical path between the source of power and the subassembly have a very low resistance. If the resistance is too high, the resulting voltage drop, aside from efficiency considerations, can cause the voltage supplied to the subassembly to be too low.
Cables are often used to electrically connect the system components. In one typical arrangement each end of the cable has a lug attached to it. The lugs have a flat surface with a hole through it for bolting the lug at one cable end to the power supply and the lug on the other end of the cable to the power distribution system of the subassembly. The diameter of the cable is made large enough to give the desired low resistance.
There are several drawbacks with this prior art cable connection method. To remove and replace a subassembly, at least one of the lugs must be unbolted before the subassembly can be removed. This usually requires some time and the use of a wrench or other tool. Another disadvantage with using cable lugs is that the lugs provide a limited surface area for electrical contact between the lugs. An electrically conductive grease can be applied to the lug surfaces to reduce this contact resistance. However, even with such grease, surface contact resistance can be substantial
Pin and socket type connectors are also commonly used in the prior art. They allow electrical connections to be easily and quickly made and broken. They may be used mounted to the ends of a cable in lieu of the lugs in the above-described cable connection system. However, the pin can be permanently affixed to either the power supply or the subassembly while the socket is permanently affixed to the other. As the subassembly is mounted within the system, the pin slides into the socket to make an electrical path for the current. Such pin and socket connecting systems are often preferred over cables since the pin and socket connectors can be designed to take up little room within the system. Unfortunately, known pin and socket connectors also have their disadvantages.
In the ideal pin and socket connector, the pin would make contact with the socket along the entire length and around the entire circumference of the pin. In practice, it is difficult to cause the pin to make such full contact with the socket. The contact resistance of the connector could be made smaller by making the pin and socket longer. However, space and strength limitations restrict how large the pin and socket can be.
One prior art pin and socket design uses flexing mechanisms, similar to small leaf springs, within the socket. When the pin is out of the socket, the opening within the socket is smaller than the pin. As the pin is inserted into the socket the flexing mechanisms are spread apart. In this design, which is expensive, contact between the pin and socket is made only at the surface of the flexing mechanisms thus limiting the area of surface contact. Also, the flexing mechanisms work-harden with use and eventually lose their spring force causing the contact resistance to increase.
Other pin and socket designs use woven sockets which expand as the pin is inserted or woven pins which compress as they are inserted into the socket. These types of connectors are also expensive and tend to have a limited life because of work-hardening.